UN Secretary General Ban Ki-moon has appealed to Haitians to be patient over efforts to bring them relief from last Tuesday's earthquake. Food and water are finally reaching some parts of the capital Port-au-Prince, but relief efforts are being slowed by bottlenecks. Haitian President Rene Preval said 3,500 US troops would help UN and Haitian forces restore order in Port-au-Prince. Speaking in Port-au-Prince, Mr Ban Ki Moon called the situation in Haiti one of the worst humanitarian crises in decades. He visited the ruins of the UN mission, where several senior UN staff were killed. The city's port is badly damaged, and many roads still blocked by corpses and debris. The UN has warned about fuel shortages, which it says could affect humanitarian operations. Estimates of how many people died following the 7.0 magnitude earthquake have varied with the Pan American Health Organization putting the death toll at 50,000-100,000.In Canada, a Donor conference will be held on 25th of this month in Montreal to discuss reconstruction efforts in the quake hit Haiti.